Emulsion layers or other hydrophilic colloidal layers in silver halide photographic materials are often colored for the purpose of absorbing light of a specific wavelength region.
When control of a spectral composition of incident light is needed, a colored layer is usually provided at the position farther from a support than a photographic emulsion layer. Such a colored layer is called a filter layer. Where there are two or more photographic emulsion layers, the filter layer is sometimes interposed between the emulsion layers.
Light scattered during or after passage through a photographic emulsion layer is reflected on the interface between an emulsion layer and a support or on the surface of a photographic material on the side opposited to a photographic emulsion layer and again enters in the photographic emulsion layer to cause image smearing, i.e., halation. In order to prevent such a phenomenon, a colored layer called an antihalation layer is usually provided between a photographic emulsion layer and a support or on the surface of a support on the side opposite to a photographic emulsion layer. Where there are two or more photographic emulsion layers, the antihalation layer is sometimes provided between these emulsion layers.
Further, coloration of a photographic emulsion layer is also conducted in order to prevent reduction of image sharpness due to light scatter within a photographic emulsion layer (this phenomenon is generally called irradiation).
The hydrophilic colloidal layer to be colored generally contains a dye. Dyes which can be used for the above purposes are required to show proper spectral absorption according to the end use, to be photochemically inert (that is, to give no chemically adverse influence on performance of a silver halide photographic emulsion layer, such as reduction in sensitivity, fading of a latent image, and fogging), to be decolorized or bleached during photographic processing or dissolved in a processing solution or washing water, leaving no harmful color in a processed photographic material, not to diffuse from a layer where they are fixed to other layers, and to exhibit excellent stability with time in solutions or in a photographic material without undergoing color change.
When in particular, the colored layer is a filter layer or an antihalation layer provided on the same side as a photographic emulsion layer with respect to a support, the dye to be used is required, in many cases, to exclusively color the desired layer without coloring other layers. Otherwise, the dye would exert harmful spectral effects on other layers and also their own effects as a filter layer or an antihalation layer would be lessened. However, when a dye-containing layer is brought into contact with other hydrophilic colloidal layer in a wet state, cases are often met in which a part of the dye in the former layer diffuses into the latter layer. Many efforts have conventionally been made in order to prevent such dye diffusion.
For example, it has been proposed to incorporate a hydrophilic polymer having a charge opposite to a dissociated anionic dye into a specific layer as a mordant to thereby localize the dye in that specific layer by the mutual action between the polymer and dye molecules, and disclosed in U.S. Pat. No. 2,548,564, 4,124,386, and 3,625,694.
Further, methods of dying a specific layer by using a water-insoluble solid dye have been suggested in JP-A-56-12639, JP-A-52-92716, JP-A-55-155350, JP-A-55-155351, JP-A-63-27838, JP-A-63-197943 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), European Patent 15,601, U.S. Pat. Nos. 4,803,150 and 4,855,221, and WO 88/04794.
Furthermore, methods of dyeing a specific layer with metallic salt fine particles on which a dye is adsorbed are disclosed in U.S. Pat. Nos.2,719,088, 2,496,841, and 2,496,843 and JP-A-60-45237.
Even with these improved methods, however, there have been pointed out problems that the rate of decoloration on development processing is still low and that the decolorizing function of the dye cannot be always taken full advantage of in cases where various alterations for improvement, such as speeding up of processing, changes in composition of processing solutions or photographic emulsions, are made.
On the other hand, it has been demanded to develop a hydrophilic colloidal layer containing a dispersion of fine solid particles of a dye which is applicable to photographic light-sensitive materials sensitive to near infrared light, for example, a dye which absorbs light having a wavelength of from 700 to 1000 nm and, also, is sufficiently decolorized or washed off during development processing. However, a dye meeting such demands has not yet been found.